Dialkylphosphite is also known as dialkyl hydrogen phosphonate. It can be made by the reaction of PCl.sub.3 with alkanol evolving HCl. Water can be included in the alkanol during this reaction (Kosolapoff et al, Organic Phosphorus Compounds, Volume 5, Page 28).
Dialkylphosphites are useful lubricant additives. For example, di-n-butylphosphite is used in gear lubricants to provide beneficial friction and wear properties. It is referred to as an extreme pressure (EP) additive.